| AVS 65th International Symposium & Exhibition | |
| Electronic Materials and Photonics Division | Monday Sessions |
| Session EM+AM+NS+PS-MoA |
| Session: | Atomic Layer Processing: Selective-Area Patterning (Assembly/Deposition/Etching) |
| Presenter: | Suzanne E. Mohney, The Pennsylvania State University |
| Authors: | S.E. Mohney, The Pennsylvania State University K.A. Cooley, The Pennsylvania State University M. Abraham, The Pennsylvania State University A.C. Domask, The Pennsylvania State University H. Simchi, The Pennsylvania State University L. Kerstetter, The Pennsylvania State University C. Lawrence, The Pennsylvania State University T.N. Walter, The Pennsylvania State University |
| Correspondent: | Click to Email |
We review our recent studies of contacts to a variety of chalcogenide semiconductors, including few-layered molybdenum disulfide and tungsten diselenide, as well as the phase-change material germanium telluride. In some cases, diffusion of a transition metal into the semiconductor has been correlated with an especially low contact resistance. For example, annealing silver contacts on field effect transistors fabricated from few-layered molybdenum disulfide resulted in a reduction in contact resistance by a factor of 4–5 to 0.2–0.7 kOhm-µm, while the ON/OFF current of the device remained high. Diffusion of silver into molybdenum disulfide was confirmed by secondary ion mass spectrometry. On the other hand, nickel appears to be even more soluble in molybdenum disulfide (as observed by Auger electron spectroscopy), but annealing nickel contacts resulted in an increase in resistance. For the phase-change material germanium telluride, incorporation of iron seems to play a role in achieving a low contact resistance of 0.004 Ohm-mm in annealed Au/Fe/Sn/p-GeTe contacts. Diffusion of iron into germanium telluride at a low but detectable level was found beneath a narrow-gap tin telluride interfacial reaction product using energy dispersive spectroscopy in the scanning transmission electron microscope. Using only iron or tin without the other did not result in such a low contact resistance. The influence of iron on the electronic properties of germanium telluride is now under study. Besides diffusion of metals into the semiconductor, we also present cases of reactive contacts to germanium telluride, whereby the contact resistance is greatly increased by interfacial reactions that led to the formation of a new phase (especially nickel tellurides and platinum tellurides). Finally, we consider the influence of surface diffusion on quasi van der Waals epitaxy of metals on layered transition metal dichalcogenides.